The identification of a primary tumor typically starts with a clinical examination, followed by imaging techniques such as X-rays, MRI, or CT scans. However, a definitive diagnosis often requires a biopsy, where a tissue sample is taken and examined under a microscope. Histological examination involves staining techniques like Hematoxylin and Eosin (H&E) staining, which can reveal cellular morphology, tumor architecture, and other distinct features.
